Spark plug



May 2.7, 1924. l 1,495,716

F.' ROYER s PARK PLUG num uw "u A 16 3 unllmx w i 38 v IV 15 M Rmllillllm df l5 I v.f 20 k w '-12 inf/@mp Patented May 27, 1924.

PATENT OFFICE.

FRANK s. ROYER, or CHICAGO, ILLINOIS.

SPARK PLUGu Application tiled January 15, 1921. Serial No. 437,552.

To all whom it may conc-em:

Be it known that I, FRANK S. ROYER, a citizen of the United States, and a resident of Chicago, in the county of Cook and State of Illinois, have invented certain nevi7 and useful Improvements in Spark Plugs; and I do hereby declare that the following is a full, clear, and exact description thereof, reference being had to the accompanying drawings, and to the charactersof reference marked thereon, which form a part of this specication.

This invention relates to improvements in spark or ignition plugs for 4the i nition systems of explosion engines, and as for its objects to provide an improved construction and arrano'elnent to protect the terminals of the plug trom short circuiting due to the contact of oil withl thel terminals at the spark gap; to novel means for insulating the live terminal from the ounded side of the plug; to mea-ns Vfor pro uciiig a durable, practically non-breakableV plug, and t0 i means fr otherwise'improving spark plugs.

In accordance with my invention, the terminals at the spark gap are enclosed within a chamber in the shell of the plug, the walls of which chamber are constructed -to permit free access t-o said chamber of thecombustible gaseous mixture under ressure and free egress `therefrom of the ame of combustion towards and' into the cylinder, while at the same time protecting the terminals from contact with oil that may be pumped into the cylinder because of leaky piston rings and other conditions. The openings into the terminal chamber can be formed between suitable baille elements, which can be made integral parts of the plugr lchamber walls, and so arranged as to afford indirect passages for the gasesV to 'l and fromV the chamber, and at the same time arranged to baffle oil thrown outwardly7 against the inner end of the plug so as to largely divert it away from said chamber and to divert any oil entering Said chamber outwardly against the walls thereof and away from the sparking terminals and thereby prevent contact of the oil with the terminals at the 'spark gap.

The means for insulating the live terminal from the grounded part of the plug structure is constructed to avoid to a large extent exposureof insulators, and especially porcelain, as heretofore employed, and to this end it is proposed to produce a substantially metal clad plug in that substantially all parts of the insulating elements of the plug are protected or supported, or both, by durable metal walls. The plu therefore, becomes practically unbreaka le, and is capable, of rough usage without injury. This metal sheath or covering can also be formed in part to constitute radiating fins wherebythe exposed portion of the plug may be maintained suitably cooled.

The construction of'the'plug body (shell and gland) is 'such thatthe spark ap between the terminals Vmaybe shortene by the sim leexpedientj of removing parts of a laminated or `shim washer'that is flocatedto form la-gasltight j'ointbetween opposing jointformi'ngs uuldersof the body.v

Otherfeatures of the construction which go to improve and simplify'tli'e spark plug will'appear from the subjoined description.

A s shown in the drawings;

Figure 1 i's a'side'elevation, on an enlarged scale, of a spark plug embodying my invention., j

Figure 2 is an axial section thereof.

Figure 3 is an end view of the plug.

Figure' is a cross section on the line 4-4 of Figure 2.

Figure 5 is a section on the line 5 5 of Figure 4.

Figure 6 is a perspectlve detail of the in-l ner end of the plug shell.

In said4 dravvin'gs, 10 designatesv as a whole the -metallicshell of the plug, which is formed with a reduced threaded portion 11 for engagement with the threaded opening in the cylinder wall or head, and with a larger olygoualv 'ortion 12. 13 designates a g and the t readedportionI 14 of which engages interior screw threads in the shell and is formed with an' annular, inwardly-facing shoulder 151that opposes a solder'formed on the outer end of the S e i Said gland 13 is formed with an out` wardly extending neck 16 and said neck and gland are provided with a through axial opening to receive a rod 17 which extends at its outer end beyond the plug. The inner end of said rod constitutes the live terininal of the plug and extends into and terminates within a chamber 3() formed in the inner reduced end of the shell. Said terminal is spaced from' the grounded terminalt 19 of the plug, also located "within said chamber 30 and grounded to the shell in a manner hereinafter' to be' described'.

2O designates an insulating body usually made of porcelain. It is centered in any suitable way with respect to the gland 13, as by means of areduced cylindric exten sion 21 which fits in an inwardly.opening socket of the land. The insulator 20 is suiliciently sma ler than the shell as to be out of contact with its metal' wall and is rounded on its inner side within the .enlarged p ortiou` of the shell chamber. The construction is such that the porcelain insulator can be made quite short. A It has an axial passage through which the terminal rod extends and closely lits, and said rod has fixed thereon a shoulder forming washer 29 that bears against the inner face of the insulator and is concaved to'fit the inner convex. end ofsaid insulator.

The axial o ening of the insulator is enlarged throng theprincipal portionof its length and is coaxial with the axial opening of t arerrnade considerabl larger than the terrriinal rod 17, .and sai rodis insulated from the Uland and; neck byan insulating sleeve 23 tliat ts closely; within said axial open: ings and` itself closely surrounds rod. A suitable insulatorfor, this Apurpose is a tube made of spirally wrapped sheet-mica,

inasmuch' as a, tube or sleeve,.thus formed'` possesses considerable flexibility and-does not easily break under dill'erentialltemperatures ini itself and in the contacting ,mjetal parts, and alsobecause itis a materialflat readily adapts itself to the ratherclose' die,

mensions indicated, andj at4 the samev timeis durable and etlicient, especially when enclosed and metal supported in the manner shown. Y Y

The laminated insulator sleeve 23' extends inwardly beyond the gland 13 into the opening or socket 22 of the insulator 20 a distance to providen long current leakage path between the said terminal rod and the gland. The said insulator sleeve 23 extends a substantial distance outwardly beyond the neck and the outer end of the terminal rod 17 is insulated from said neck by a suitable insulatingwasher 24 having a central opening into which closely lits said insulator sleeve or tube 23. The said washer can, and prefcrably is made ofsheet-mica, the lamin' of which are pressed and held firmly between inner and outer washers 25, 26 b v the clamping action of a nut 27 that cooperates against a shoulder formed by the outer end of the veel; 16. Said-terminal rod 17 extends beyond the nut 2T to receive the usual e gland and neck. The latter openings thumb nut 28 to constitute a familiar type of binding post for the plug. The shoulder piece 29 constitutes a limiting stop between which and the n'ut 27 the parts are clamped together.

The said insulator' washer or disc 24 is per'ipherally beveled oppositely from a median planel towards its upper and lower sides, being of largest diameter at said median plane. Thus the path of current leakage between the upper and lower washers is considerably increased, with the result of ample insulation between the gland neck and the outer end oi' the terminal rod. This formation of the insulator washer also gives it the additional function of divertingr water, which may fall on the washer, outwardly away from the parts oi' the plug body. The neck 16 can be formed below the insulating washer with fins 38 to constitute the elements of a radiator to maintain suitably cool the exposed portions of the plug. It will be noted also that said fins are of gradually decreasing diameter rom the inner end of the neck outwardly and that the peripheries of the' fins are beveled so' as to avoid lodgement of water on this 'part of theplug. The lin 'formation materially lightens the plug.

The construct-ion described, wherein the insulator tube or sleeve 23 is enclosed by the metallic neck 16 or analogous part of the metal body of the plug, possesses considerable practical advantage, inasmuch as the plug is free of exposed insulating parts, as the usual porcelain insulator. wliichare liabletobe fractured, andwhich, upon fracture, short circuits the plug. The plug is, therefore, sturdy and capable ot hard usage without injury. 4

Referring now to the construction of the inner end ofv the shell and to the means for protecting the terminals from contact with oilwhich may be pumped into the cylinder, the-parts'are made as follows: v

The saidfinner end of the shell is of general part-spherical. or concavo-convex formation. Itisformed diametrically across said end with a deep groove 31 having a fiat bottom member 32 that constitutes a baffle element, as will hereinafter more fully appear. The plane of said element 32 is considerably above or exterior to the inner concave surface of said end. as best shown in Figures 2 and 5. thereby forming at the sides of` the groove 31 segmental chambers 33 bounded b v spherically segmental walls 34. 35 designate slits that are cut. into the spherically shaped end wall at opposite sides of the shell. The plane of said slits is transverse to the plane of the axis of the shell and preferably below or inside theplane of the ballie'eler'nent- 32,`as besty shown in Figure 5. The battle element 32 is wider than the slit 31. so that its side edges extend laterally beyond the inner' or proximate edges of the .55, said baille element being wider inherent novelty shown in the. drawings and described in the specification.

l claim as my invention:

1:. A spark plug embracing a body formed atfit's inner end with a chamber enclosing spaced, central terminals, the inner or en wall of said chamber being provided with a passage which permits free ingress of gas to and ogressof burning Amixture from said chamber and with a baille element between the passage and terminals wider than said passage, with its edge so r'elated lo the wall of the passage as to deflect oil entering the chamber outwardly away from said' terminals, said chamber wall beingprovjded opposite said edges with lateral passa'gesfl' y A A spark plug for the ignition system ofV csplosion engines comprlsing a shell, a live'lferlminal insulated from said shell and extendin into a chamber at the inner end of sa.idi s1ell, and a terminal grounded on said shell wholly within said chamber from the live terminal by a P'ak, gap, inner Eend of said shell beingV formed p at its' inner' endandsides with outwardly and laterally. ,indirect passagewayswfor gases formedlbyoverlapping baflle elements which ballleelitnfcetb sai chamber of cylinder gil', V

, I3. -:A splii'k plug' embracing two terminals betdcen which is formed a spark gap and a."supporting body therefor having at its cylindexjend a. chamber to wholly enclose said terminals', the end wall of said chamber being part sphericaluand formed with an inwardly' 'openingidia-metric slot bounded at its'outeitside'by a baille element,v and thel s'i'd'esfoi said wall :being provided with opposed: slits -which open chamber substantially op osing but lower :han the edges of said ba e element.

3l; A spark plug embracing two terminals between which is formed a spark gap and a supporting body therefor having at its cylinder end a chamber to wholly enclose said terminals, the wall of said chamber being part spherical and formed with an inwardly openin ,l diametric slot bounded at its outer side iy a baille element, and the sides of said `{vall being provided with slits which, open laterally toward said chamber, than said slots.

5. A spark plug embracing two terminals between whichis Aformed aspark gap and a supporting body therefor having at its the wall of said chamber at the laterally toward said cylinder end a chamber to wholly enclose .said terminals, the walll of said chamber being part spherical and formed with an inwardl y opening dia-metric slot bounded at its' outer side by a baille element, and the sides ol said wall being provided with slits which open laterally toward said'chamber, the lateral slits being located in a planeinside the plane of said baille element'.

ll. .i spark plug embracing two terminals between which is' formed a spark gap and a supporting body therefor having at its cylinder end a chamber-'to wholly enclose said. terminals, the'wall of said chamber lzs-ing part spherical and formed with'an in n'ardly opening liametric slot bounded at its outer side by a' baffle element, wider than said slot,` and the sides of said Wall leno provided 'with o posed slits which open laterally toward sa dchamber grounded terminal being supported baille element,

T'.' Aljspa'rli 'plug 'comprising a. shell open :it its outer end, grounded teiminal supported by the inner end of said shell, 'an elongated tubular gland member closing said shell, a' live terminal member. coperatiig with 'the grounded terminal and extending outwardly through sfaidftubiilagladmeiir ber; an insulator tubel within' vsaid' tubular gland member and surroundin terminal nie'mber toa'.l peint'1 ,'yon'd: the' rgland member, and an insulating discharing means to press it against the' outer end of said gland member and formed to receive the outer e'nd of said insulator tube.

S. A spark plug comprising a shell open at its outer en'd, a grounded termina-Islipv ported bythe inner end of'said shell, an elongated tubular gland member closing said shell, a live terminal member cooperating with the grounded terminal and extending outwardly through said tubular gland member, an insulator tube within said tubular gland member and surrounding said live terminal member to .a point beyond the gland member. and an insulating disc having means to press it against the outer end nl said gland member and formed to reire the cuter end of said insulator tube, said disc overhanging the upper end of said gland and being formed with a tapered or wedge shaped periphery.

ln witness whereof I claim the foregoing as my invention, I hereunto append my signature this l2 day of January, 1921.

FRANK s. ROYER.

on Said the said' 

